Task 1.2 - Make a Resource Act Like a List

Task Overview

Up to this point, you've built a basic transportation task sequence for the two task executers in the model. You can actually create this basic functionality without using the Process Flow tool. However, the real power in using the Process Flow tool is how easy it is to create custom model logic, especially for task sequences.

In this tutorial task, you'll add process flow logic that will occasionally interrupt the operator's normal transportation task sequences. You'll design logic that will send operators to a get a drink from the drinking fountain every time they travel more than 100 meters.

In order to create this logic, you'll build an additional section in the process flow for a water break task sequence. Also, recall from the previous tutorial that the resource shared asset is linked to the two operators in the 3D model. In order to create the water break tasks, you'll need the resource shared asset to keep track of the distance the operators have traveled. For that reason, you'll need to change the resource so that it acts a little more like the list. Lists can track and update data about the entries on the list; you can also build queries that pull entries from the list that match specific criteria.

Fortunately, resources actually have an internal list that you can set up to have the same functionality as a list. In this tutorial task, you'll learn how to set up the resource's internal list to track the total distance the operators have traveled in the simulation model and the distance they've traveled since their last water break. You'll also design a query so that your water break task sequence will pull any operators who have traveled more than 100 meters since their last water break.

When you're finished, your model will work similar to the following image:

Step 1 Use the Internal List on a Resource

Now that your basic transportation task sequence is set up, you'll create a series of tasks that will occasionally pull the operator away from their normal transportation tasks and send them to get a drink of water. You'll want to simulate the operator getting a drink from the drinking fountain after the operator has traveled more than 100 meters.

By now you may have noticed that the list and resource shared assets have somewhat similar functions. In fact, resources are simply a special kind of list. The resource you're using in this process flow actually keeps an internal list of the available operators. The Acquire Resource and Release Resource activities push and pull operators from this list.

In this step, you'll need to add some fields to this internal list in order to add the water break functionality in a later step. You'll add two fields:

• lastDrinkTotalTravel - You'll add a field that creates a label on the operator called lastDrinkTotalTravel. This label will track the distance the operator has traveled since it took its last water break. The process flow will update this label after each operator takes a water break.
• totalTravel - You'll also add a field that tracks the total distance the operator has traveled since the simulation began running. All operator 3D objects keep track of their total distance traveled as a standard (default) statistic in FlexSim. So, you'll add a field to the resource's list that gets the current value of the statistic.

To add these fields to the resource's internal list:

1. Click the Resources: Operators shared asset to select it.
2. In Properties, click the Advanced button to open this resource's list properties.
3. In the Fields tab, click the Add button to open a menu. Select Label to add a label field to the list.
4. Change the name of the label field to lastDrinkTotalTravel.
5. Click the Add button to open a menu. Point to TaskExecuter, then select totalTravel.
6. You'll use the default settings, so confirm that they look similar to the following image:

Consider saving your simulation model.

Step 2 Add a Water Break Task Sequence

In this step, you'll add some more activities to the process flow. These activities will control the water break functionality. When you're finished, your process flow will look similar to the following image:

For now, you'll merely add and connect these activities to the process flow. You'll edit the properties to add the functionality in a later step.

To add and connect these activities:

1. Make sure the process flow is open and active.
2. In the Library under the Display group, add an additional Container shape to the new process flow.
3. For clarity, rename the Process shape Water Breaks.
4. Add a Schedule Source to the Water Breaks shape.
5. In the Water Breaks shape, add the following activities to create a stacked block:
   • An Acquire Resource activity (under Shared Assets)
   • A Create Task Sequence (under Task Sequences)
   • A Travel > Travel to Object activity (under Task Sequences)
   • A Delay activity (under Task Sequences)
   • An Assign Labels activity (under Basic)
   • A Finish Task Sequence (under Task Sequences)
   • A Release Resource activity (under Shared Assets)
6. Create a connector from the Schedule Source to the Acquire Resource. (Point your mouse over the bottom middle of the activity until your mouse changes to a connector icon. Click and drag the connector until it snaps to the other activity.)
7. Create a connector that loops from the end of the Release Resource activity back to the Acquire Resource activity.
8. For clarity, rename the activities as follows:

Activity	New Name
Source	Source: Start Simulation
Acquire	Acquire: Get Thirsty Operator
Create TS	Create Task Sequence
Travel	Travel to Water Fountain
Delay	Delay: Drinking
Assign Labels	Assign Labels: lastDrinkTotalTravel
Finish TS	Finish Task Sequence
Release	Release Operator

Consider saving your simulation model.

Step 3 Edit the Activity Properties

In this step, you'll edit the properties for the activities in the Water Break section of the process flow to create a simple transportation task sequence. The following is an overview of how each activity in this section will function:

To edit these activity properties:

1. Click the Scheduled Source activity to select it. You'll use the default properties for this activity, so confirm that the settings match the following image:



2. Next to the Acquire: Get Thirsty Operator activity, click the Exclamation Point button to enter sampling mode.
3. Click the Resources: Operators in the process flow to sample it. A blue line will appear to show that the resource is now linked.
4. In Properties for the Acquire: Get Thirsty Operator activity, change the Assign to Label box to token.thirstyOperator.
5. In the Query box, delete the current text and type WHERE totalTravel - lastDrinkTotalTravel > 100.



6. Click the Create Task Sequence activity to select it. In Properties, click the arrow next to the Task Executer / Dispatcher box to open a menu. Point to Token Label and select thirstyOperator. This will assign the task sequence we are creating to the operator previously acquired. Leave the other settings as their default values. You'll notice that this activity creates a new label on the token called taskSequence. All of the tasks in this sequence will be assigned to the sequence via this label.



7. In Properties for the Travel to Water Fountain activity make sure the default for Executer / Task Sequence reads token.taskSequence.
8. Next to the Destination box, click the Sampler button to enter sampling mode.
9. Click the Fountain shape in the 3D model to open a menu. Select Fountain from the menu.



10. In Properties for the Delay: Drinking activity make sure the default for Executer / Task Sequence reads token.taskSequence. Then, change the Delay Time to 30.



11. In Properties for the Assign Labels: lastDrinkTotalTravel activity, click the arrow next to the Assign Labels To box to open a menu. Point to Token Label and select thirstyOperator.
12. In the Name box, delete the current text and type lastDrinkTotalTravel.
13. In the Value box, type getvarnum(token.thirstyOperator, "totaltraveldist").



14. We can leave the Finish Task Sequence as its default settings. Make sure the Task Sequence box reads token.taskSequence. This designates the end of the sequence of tasks to be carried out.
15. In Properties for the Release Operator activity, click the arrow next to the Resource(s) Assigned To box to open a menu. Point to Token Label and select thirstyOperator.

Consider saving your simulation model.

Step 4 Add Labels to the Operators

In this step, you'll add the lastDrinkTotalTravel label to the operators and set its initial value to 0. You need to do this in order for the logic to work. Unless you set the initial value to 0, this label will return a NULL value when calculating how long it has been since the operator last took a drink. If that happens, the Acquire: Get Thirsty Operator activity won't be able to successfully pull an operator from the resource's internal list.

To add these labels:

1. Reset the model.
2. Click the Operator to bring up its properties on the right.
3. Under the Labels section, click the Add button to open a menu. Select Add Number Label.
4. Double click the labelName box, delete the current text and type lastDrinkTotalTravel.
5. Confirm that the label's initial value is set to 0.
6. Check the Automatically Reset checkbox.
7. Repeat this process for the second operator.

Consider saving your model.

Step 5 Run the Simulation Model

In this step, you'll run the simulation model to ensure that it is functioning correctly. Before running the model:

1. On the simulation control panel, click the Reset and Run buttons. Run the simulation for a second and then click the Stop button.
2. In the process flow, click the Resources: Operators shared asset to select it. In Properties, click the View Entries button to view the resource's internal list.
3. Back on the simulation control panel, click the Reset and Run buttons.

Be aware that the following model is being run at speed 10.00:

As the model runs, notice that when the operators travel more than 100 meters, they go to get a drink from the drinking fountain. After their first drink, the resource's list begins tracking the amount of travel from their last drink.

Conclusion

Now you've seen some of the different possible uses for both resources and lists. In the next tutorial task, you'll learn how to use the last type of shared asset: the zone. Continue on to Tutorial Task 1.3 - Add a Zone to Collect Data.